Effect of mobile interventions with nicotine replacement therapy sampling on long-term smoking cessation in community smokers: A pragmatic randomized clinical trial

INTRODUCTION Mobile interventions enable personalized behavioral support that could improve smoking cessation (SC) in smokers ready to quit. Scalable interventions, including unmotivated smokers, are needed. We evaluated the effect of personalized behavioral support through mobile interventions plus nicotine replacement therapy sampling (NRT-S) on SC in Hong Kong community smokers. METHODS A total of 664 adult daily cigarette smokers (74.4% male, 51.7% not ready to quit in 30 days) were proactively recruited from smoking hotspots and individually randomized (1:1) to the intervention and control groups (each, n=332). Both groups received brief advice and active referral to SC services. The intervention group received 1-week NRT-S at baseline and 12-week personalized behavioral support through SC advisor-delivered Instant Messaging (IM) and a fully automated chatbot. The control group received regular text messages regarding general health at a similar frequency. Primary outcomes were carbon monoxide-validated smoking abstinence at 6 and 12 months post-treatment initiation. Secondary outcomes included self-reported 7-day point-prevalence and 24-week continuous abstinence, quit attempts, smoking reduction, and SC service use at 6 and 12 months. RESULTS By intention-to-treat, the intervention group did not significantly increase validated abstinence at 6 months (3.9% vs 3.0%, OR=1.31; 95% CI: 0.57–3.04) and 12 months (5.4% vs 4.5%, OR=1.21; 95% CI: 0.60–2.45), as were self-reported 7-day point-prevalence abstinence, smoking reduction, and SC service use at 6 and 12 months. More participants in the intervention than control group made a quit attempt by 6 months (47.0% vs 38.0%, OR=1.45; 95% CI: 1.06–1.97). Intervention engagement rates were low, but engagement in IM alone or combined with chatbot showed higher abstinence at 6 months (adjusted odds ratios, AORs=4.71 and 8.95, both p<0.05). CONCLUSIONS Personalized behavioral support through mobile interventions plus NRT-S did not significantly improve abstinence in community smokers compared to text only messaging. The suboptimal intervention engagement needs to be addressed in future studies. TRIAL REGISTRATION ClinicalTrials.gov NCT04001972.

yes: all primary outcomes were signi cantly better in intervention group vs control partly: SOME primary outcomes were signi cantly better in intervention group vs control no statistically signi cant difference between control and intervention potentially harmful: control was signi cantly better than intervention in one or more outcomes inconclusive: more research is needed Other: not submitted yet -in early draft status not submitted yet -in late draft status, just before submission submitted to a journal but not reviewed yet submitted to a journal and after receiving initial reviewer comments submitted to a journal and accepted, but not published yet published Other: Approx. Percentage of Users (starters) still using the app as recommended after 3 months

Tobacco Induced Diseases
Is this a full powered effectiveness trial or a pilot/feasibility trial? * Manuscript tracking number * If this is a JMIR submission, please provide the manuscript tracking number under "other" (The ms tracking number can be found in the submission acknowledgement email, or when you login as author in JMIR. If the paper is already published in JMIR, then the ms tracking number is the four-digit number at the end of the DOI, to be found at the bottom of each published article in JMIR) The paper is not a JMIR submission. Identify the mode of delivery. Preferably use "web-based" and/or "mobile" and/or "electronic game" in the title. Avoid ambiguous terms like "online", "virtual", "interactive". Use "Internet-based" only if Intervention includes non-web-based Internet components (e.g. email), use "computer-based" or "electronic" only if o ine products are used. Use "virtual" only in the context of "virtual reality" (3-D worlds). Use "online" only in the context of "online support groups". Complement or substitute product names with broader terms for the class of products (such as "mobile" or "smart phone" instead of "iphone"), especially if the application runs on different platforms.
C l e a r s e l e c t i o n Does your paper address subitem 1a-i? * Copy and paste relevant sections from manuscript title (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study mobile health technologies

1a-ii) Non-web-based components or important co-interventions in title
Mention non-web-based components or important co-interventions in title, if any (e.g., "with telephone support").
C l e a r s e l e c t i o n Does your paper address subitem 1a-ii?
Copy and paste relevant sections from manuscript title (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study nicotine replacement therapy sampling 1a-iii) Primary condition or target group in the title Does your paper address subitem 1a-iii? * Copy and paste relevant sections from manuscript title (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study long-term  Does your paper address subitem 1b-i? * Copy and paste relevant sections from the manuscript abstract (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study Both groups received brief advice and active referral to SC services. The intervention group received 1-week NRT-S at baseline and 12-week behavioral support through SC advisordelivered IM and a fully automated chatbot. The control group received regular text messages regarding general health at a similar frequency.

1b-ii) Level of human involvement in the METHODS section of the ABSTRACT
Clarify the level of human involvement in the abstract, e.g., use phrases like "fully automated" vs. "therapist/nurse/care provider/physician-assisted" (mention number and expertise of providers involved, if any). Does your paper address subitem 1b-ii?
Copy and paste relevant sections from the manuscript abstract (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study The intervention group received 1-week NRT-S at baseline and 12-week behavioral support through SC advisor-delivered IM and a fully automated chatbot.
1b-iii) Open vs. closed, web-based (self-assessment) vs. face-to-face assessments in the METHODS section of the ABSTRACT Mention how participants were recruited (online vs. o ine), e.g., from an open access website or from a clinic or a closed online user group (closed usergroup trial), and clarify if this was a purely web-based trial, or there were face-to-face components (as part of the intervention or for assessment). Clearly say if outcomes were self-assessed through questionnaires (as common in web-based trials). Note: Copy and paste relevant sections from the manuscript abstract (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study 664 adult daily cigarette smokers (74.4% male, 51.7% not ready to quit in 30 days) were proactively recruited from smoking hotspots 1b-iv) RESULTS section in abstract must contain use data Report number of participants enrolled/assessed in each group, the use/uptake of the intervention (e.g., attrition/adherence metrics, use over time, number of logins etc.), in addition to primary/secondary outcomes. (Note: Only report in the abstract what the main paper is reporting. If this information is missing from the main body of text, consider adding it) Does your paper address subitem 1b-iv?
Copy and paste relevant sections from the manuscript abstract (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study Intervention engagement rates were low (IM only: 22.3%; chatbot only: 4.0%; both: 7.0%), but engagement in IM alone or combined with chatbot showed higher abstinence at 6 months (adjusted ORs=4.71 and 8.95, both P<0.05).

1b-v) CONCLUSIONS/DISCUSSION in abstract for negative trials
Conclusions/Discussions in abstract for negative trials: Discuss the primary outcome -if the trial is negative (primary outcome not changed), and the intervention was not used, discuss whether negative results are attributable to lack of uptake and discuss reasons. Copy and paste relevant sections from the manuscript abstract (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study mHealth technologies plus NRT-S did not significantly improve abstinence in community smokers. The low intervention engagement needed to be addressed in future studies.

2a-i) Problem and the type of system/solution
Describe the problem and the type of system/solution that is object of the study: intended as stand-alone intervention vs. incorporated in broader health care program? Intended for a particular patient population? Goals of the intervention, e.g., being more cost-effective to other interventions, replace or complement other solutions? (Note: Details about the intervention are provided in "Methods" under 5) Does your paper address subitem 2a-i? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study Longer term effect of mHealth SC interventions is uncertain as few RCTs (15%) had a follow up beyond 6 months. The population-level effect of mHealth interventions remains unknown as many who do not want to quit or plan to quit were not included. mHealth interventions in the community smokers with longer follow-up length are needed. The present RCT developed a chatbot in addition to the established AWARD model, IMbased intervention, and NRT-S. We aimed to evaluate the long-term (6 and 12 months) effect of such a combined intervention on smoking abstinence in Hong Kong community smokers. Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study Instant messaging (IM, e.g., WhatsApp, WeChat) is a popular and inexpensive alternative to SMS. Our qualitative interviews on community smokers (76% had no quit plan in the next 6 months) showed that the provision of more personalized behavioral support from human SC advisors was the most valued utility of IM for SC.8 Our pragmatic RCT further showed that IM intervention was effective for SC in community smokers.9 However, the intervention engagement rate was low (17%), which might be due to the unavailability of human SC advisors outside office hours.9 SC support could be sustained using chatbots (also known as conversational agents), online computer programs that can simulate human conversations. Evidence on chatbots for SC is emerging but remains scarce and limited. A formative study showed that a chatbot increased motivation to quit immediately after usage in a volunteer sample of young smokers.10 An RCT focusing on smokers motivated to quit identified that adding a chatbot to an SC app more than doubled intervention engagement with the app (incidence rate ratios=2.01, 95% CI 1.92, 2.11), but the effect on SC was unclear because of a low retention rate at 1 month (10.7%).11 A pragmatic RCT in primary care settings showed that a chatbot was marginally more effective than usual care (biochemically validated abstinence at 6 months: odds ratio[OR]=1.52, 95% CI 1.00, 2.31; P=0.05) despite of potential non-response bias due to a low retention rate (45.2%). 12 The interventions in the present RCT were developed based on established evidence of our prior studies and RCTs. We have developed and tested an approach13 of proactively reaching community smokers who were largely unmotivated to quit and reasonably representative of the general smoking population regarding their sociodemographic and smoking characteristics.9,14 Our 2015 RCT in the proactively recruited community smokers showed that brief advice using the AWARD model (Ask, Warning, Advice, Referral, Do-itagain) was effective for SC. 15 Our 2017 RCT further developed the IM-based intervention combined with the AWARD model and supported the effectiveness for SC.9 Nicotine replacement therapy sampling (NRT-S) has been used in unmotivated smokers and was found to be effective for increasing quit attempts and full-course NRT use.16 A recent RCT in unmotivated smokers showed that mHealth intervention plus NRT-S led to higher abstinence at 6 months than NRT-S alone.17 Our pilot RCT showed that the IM-based intervention plus NRT-S was feasible with positive effects on quitting, smoking reduction, quit attempts, and NRT-S use in community smokers.18 Does your paper address CONSORT subitem 2b? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study The present RCT developed a chatbot in addition to the established AWARD model, IMbased intervention, and NRT-S. We aimed to evaluate the long-term (6 and 12 months) effect of such a combined intervention on smoking abstinence in Hong Kong community smokers.
3b) Important changes to methods after trial commencement (such as eligibility criteria), with reasons subitem not at all important 1 2 3 4 5 essential 4a) Eligibility criteria for participants Does your paper address CONSORT subitem 3a? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study This was a two-arm, parallel, assessor-blinded randomized controlled trial; The randomization sequence with a 1:1 allocation ratio and permuted block of 4, 8, or 12 was generated by a non-investigator.
Does your paper address CONSORT subitem 3b? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study Does your paper address CONSORT subitem 4a? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study We recruited Hong Kong resident aged ≥18 years who was able to read and communicate in Chinese; currently smoked at least one cigarette daily, validated by an exhaled carbon monoxide level of ≥4 parts per million (ppm); and owned a smartphone and were willing to install an IM app (if not already installed).

4a-i) Computer / Internet literacy
Computer / Internet literacy is often an implicit "de facto" eligibility criterion -this should be explicitly clari ed.
C l e a r s e l e c t i o n Does your paper address subitem 4a-i?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study Computer/internet literacy was not measured and has been acknowledged as a limitation.
4a-ii) Open vs. closed, web-based vs. face-to-face assessments: Open vs. closed, web-based vs. face-to-face assessments: Mention how participants were recruited (online vs. o ine), e.g., from an open access website or from a clinic, and clarify if this was a purely web-based trial, or there were face-to-face components (as part of the intervention or for assessment), i.e., to what degree got the study team to know the participant. In online-only trials, clarify if participants were quasi-anonymous and whether having multiple identities was possible or whether technical or logistical measures (e.g., cookies, email con rmation, phone calls) were used to detect/prevent these.  Information given during recruitment. Specify how participants were briefed for recruitment and in the informed consent procedures (e.g., publish the informed consent documentation as appendix, see also item X26), as this information may have an effect on user self-selection, user expectation and may also bias results.
C l e a r s e l e c t i o n Does your paper address subitem 4a-iii?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study Smokers were asked about smoking behaviors, assessed exhaled carbon monoxide level, and invited to participate in the study. Those showing interests were assessed for eligibility, and written informed consents were sought.
Does your paper address CONSORT subitem 4b? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study Eligible participants completed a brief self-administered baseline questionnaire to provide data on sociodemographic and smoking characteristics and quality of life. To avoid intervention contamination, 1 smoker was randomly approached when there were more smokers at the same hotspot. Smoking-related outcomes were measured in follow-up questionnaires through telephone interviews at 3, 6, and 12 months after randomization (intervention initiation), and quality of life was additionally assessed at 12 months.

4b-i) Report if outcomes were (self-)assessed through online questionnaires
Clearly report if outcomes were (self-)assessed through online questionnaires (as common in web-based trials) or otherwise. Does your paper address subitem 4b-i? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study Smoking-related outcomes were measured in follow-up questionnaires through telephone interviews at 3, 6, and 12 months after randomization (intervention initiation), and quality of life was additionally assessed at 12 months. Does your paper address subitem 4b-ii?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study Your answer

5-i) Mention names, credential, affiliations of the developers, sponsors, and owners
Mention names, credential, a liations of the developers, sponsors, and owners [6] (if authors/evaluators are owners or developer of the software, this needs to be declared in a "Con ict of interest" section or mentioned elsewhere in the manuscript). Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study

5-ii) Describe the history/development process
Describe the history/development process of the application and previous formative evaluations (e.g., focus groups, usability testing), as these will have an impact on adoption/use rates and help with interpreting results.
C l e a r s e l e c t i o n Does your paper address subitem 5-ii?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study Regular IM messages were guided by the Social Cognitive Theory (SCT), covering information such as knowledge and skills of quitting, benefits of quitting, strategies to manage urges to smoke for self-efficacy, and SC services, for example, "Please identify the important things in your life, which may be related to personal or family health, interpersonal relationships, finances, or others. The important thing can be the driving force for quitting smoking!" The schedule of messages was adjusted to the participants' baseline readiness to quit (within next 7 days/ 30 days/ 60 days or undecided) as according to the Transtheoretical Model (TTM).
Responses to the questions were drafted based on our previous experience in SC counseling and had been further refined according to comments from experienced SC counselors and service users in Tung Wah Group of Hospitals Integrated Centre on Smoking Cessation, one of the main SC service providers in Hong Kong. Then, a prototype had been built using IBM Watson and pilot-tested in 5 smokers recruited from smoking hotspots. The final version of Chatbot was incorporated with Application Programming Interface with a backend server support and continuous data collection.

5-iii) Revisions and updating
Revisions and updating. Clearly mention the date and/or version number of the application/intervention (and comparator, if applicable) evaluated, or describe whether the intervention underwent major changes during the evaluation process, or whether the development and/or content was "frozen" during the trial. Describe dynamic components such as news feeds or changing content which may have an impact on the replicability of the intervention (for unexpected events see item 3b).
C l e a r s e l e c t i o n Does your paper address subitem 5-iii?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study

5-iv) Quality assurance methods
Provide information on quality assurance methods to ensure accuracy and quality of information provided [1], if applicable.
C l e a r s e l e c t i o n Does your paper address subitem 5-iv?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study The final version of Chatbot was incorporated with Application Programming Interface with a backend server support and continuous data collection... Each participant in the intervention group received a unique link to access the chatbot for tracking individual's engagement.

5-v)
Ensure replicability by publishing the source code, and/or providing screenshots/screen-capture video, and/or providing flowcharts of the algorithms used Ensure replicability by publishing the source code, and/or providing screenshots/screencapture video, and/or providing owcharts of the algorithms used. Replicability (i.e., other researchers should in principle be able to replicate the study) is a hallmark of scienti c reporting.
C l e a r s e l e c t i o n Does your paper address subitem 5-v?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study Please see Supplement file 3.

5-vi) Digital preservation
Digital preservation: Provide the URL of the application, but as the intervention is likely to change or disappear over the course of the years; also make sure the intervention is archived (Internet Archive, webcitation.org, and/or publishing the source code or screenshots/videos alongside the article). As pages behind login screens cannot be archived, consider creating demo pages which are accessible without login. Does your paper address subitem 5-vi?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study URL is presented as follows: https://quitbuddy-bot.hkuteli.net/api/web/users; The interventions had been archived in local server.

5-vii) Access
Access: Describe how participants accessed the application, in what setting/context, if they had to pay (or were paid) or not, whether they had to be a member of speci c group. If known, describe how participants obtained "access to the platform and Internet" [1]. To ensure access for editors/reviewers/readers, consider to provide a "backdoor" login account or demo mode for reviewers/readers to explore the application (also important for archiving purposes, see vi).
C l e a r s e l e c t i o n Does your paper address subitem 5-vii? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study The chatbot was designed as web-based considering that unmotivated smokers were found to be unlikely to download apps for SC. Each participant in the intervention group received a unique link to access the chatbot for tracking individual's engagement.

5-viii) Mode of delivery, features/functionalities/components of the intervention and comparator, and the theoretical framework
Describe mode of delivery, features/functionalities/components of the intervention and comparator, and the theoretical framework [6] used to design them (instructional strategy [1], behaviour change techniques, persuasive features, etc., see e.g., [7,8] for terminology). This includes an in-depth description of the content (including where it is coming from and who developed it) [1]," whether [and how] it is tailored to individual circumstances and allows users to track their progress and receive feedback" [6]. This also includes a description of communication delivery channels and -if computer-mediated communication is a component -whether communication was synchronous or asynchronous [6]. It also includes information on presentation strategies [1], including page design principles, average amount of text on pages, presence of hyperlinks to other resources, etc. Does your paper address subitem 5-viii? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study Regular IM messages were guided by the Social Cognitive Theory (SCT), covering information such as knowledge and skills of quitting, benefits of quitting, strategies to manage urges to smoke for self-efficacy, and SC services, for example, "Please identify the important things in your life, which may be related to personal or family health, interpersonal relationships, finances, or others. The important thing can be the driving force for quitting smoking!" The schedule of messages was adjusted to the participants' baseline readiness to quit (within next 7 days/ 30 days/ 60 days or undecided) as according to the Transtheoretical Model (TTM).
SC advisors interacted in real-time with smokers through IM, providing behavioral support to avoid or handle high risk situations of smoking (e.g. cigarette invitation from friends), instruct the use of NRT-S and break the habitual smoking by time-contingent messages (e.g. first cigarette in the morning). Proactive IM messages such as asking about recent progress of SC were used to initiate the conversation, for example, "During this period of time, I have heard lots of good news one after another. Some people said that they had completely quit smoking, and some had reduced smoking. How about your progress? You can share it with me." SC advisors delivered SCT-and TTM-guided advice and actively referred the smokers if they expressed the need for SC services.
Each participant in the intervention group received a unique link to access the chatbot for tracking individual's engagement. SC advisors proactively sent a total of 6 reminders of chatbot URL through IM every two weeks during the 12-week personalized behavioral support.
The control group received the same AWARD model as the intervention group at baseline, an established standard care model for Hong Kong community smokers. They additionally received the regular SMS messages on healthy lifestyles and reminders to participate in the follow-up surveys for quitting, with a similar frequency to the regular IM sent to the intervention group.

5-ix) Describe use parameters
Describe use parameters (e.g., intended "doses" and optimal timing for use). Clarify what instructions or recommendations were given to the user, e.g., regarding timing, frequency, heaviness of use, if any, or was the intervention used ad libitum. Does your paper address subitem 5-ix?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study All participants received a message once a week for initiating IM conversation. The frequency increased to once daily for the week of the targeted quit date and twice weekly for the week before and after the week of the quit date. The schedule could be adjusted as requested by smokers during IM conversation.
SC advisors interacted in real-time with smokers through IM, providing behavioral support to avoid or handle high risk situations of smoking (e.g. cigarette invitation from friends), instruct the use of NRT-S and break the habitual smoking by time-contingent messages (e.g. first cigarette in the morning). Proactive IM messages such as asking about recent progress of SC were used to initiate the conversation, for example, "During this period of time, I have heard lots of good news one after another. Some people said that they had completely quit smoking, and some had reduced smoking. How about your progress? You can share it with me." Each participant in the intervention group received a unique link to access the chatbot for tracking individual's engagement. SC advisors proactively sent a total of 6 reminders of chatbot URL through IM every two weeks during the 12-week personalized behavioral support.

5-x) Clarify the level of human involvement
Clarify the level of human involvement (care providers or health professionals, also technical assistance) in the e-intervention or as co-intervention (detail number and expertise of professionals involved, if any, as well as "type of assistance offered, the timing and frequency of the support, how it is initiated, and the medium by which the assistance is delivered". It may be necessary to distinguish between the level of human involvement required for the trial, and the level of human involvement required for a routine application outside of a RCT setting (discuss under item 21 -generalizability).
C l e a r s e l e c t i o n

Does your paper address subitem 5-x?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study As an extension of the AWARD model at baseline, the intervention group received 12-week personalized behavioral support delivered through SC advisor-delivered IM and a fully automated chatbot.
subitem not at all important

5-xi) Report any prompts/reminders used
Report any prompts/reminders used: Clarify if there were prompts (letters, emails, phone calls, SMS) to use the application, what triggered them, frequency etc. It may be necessary to distinguish between the level of prompts/reminders required for the trial, and the level of prompts/reminders for a routine application outside of a RCT setting (discuss under item 21 -generalizability).
C l e a r s e l e c t i o n Does your paper address subitem 5-xi? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study SC advisors proactively sent a total of 6 reminders of chatbot URL through IM every two weeks during the 12-week personalized behavioral support.

5-xii) Describe any co-interventions (incl. training/support)
Describe any co-interventions (incl. training/support): Clearly state any interventions that are provided in addition to the targeted eHealth intervention, as ehealth intervention may not be designed as stand-alone intervention. This includes training sessions and support [1]. It may be necessary to distinguish between the level of training required for the trial, and the level of training for a routine application outside of a RCT setting (discuss under item 21 -generalizability. C l e a r s e l e c t i o n 6a) Completely defined pre-specified primary and secondary outcome measures, including how and when they were assessed Does your paper address subitem 5-xii? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study Both groups received brief advice using the AWARD model (Ask, Warning, Advice, Referral, Do-it-again) 15 at baseline. Participants were asked about smoking behaviors (Ask) and invited for an exhaled carbon monoxide test. The results were used to warn about the harms of continued smoking together with a leaflet (eFigure 1 in Supplement 2) containing shocking pictures of smoking-induced diseases (Warn). Participants were advised to quit promptly using NRT or SC services (Advise) and offered referral to a free SC service (Refer). Contacts of the participants were sent to the SC service providers of their choice for further treatment (active referral). 15 The above advice was repeated during follow-ups (Do-itagain).
The intervention group additionally received 1-week free NRT-S (Nicotinell; GlaxoSmithKline, Brentford, London, UK) in the original packing (7 NRT patches or 84 pieces of gum). Our previous trial found no difference in quit rates between 1-week or 2-week NRT-S. 22 The dose of the NRT-S was assigned based on the time to the first cigarette of the day.23 Participants who had their first cigarettes > 30 minutes after waking up and had not previously used NRT received 2 mg nicotine gum or 14 mg nicotine patch, while those who smoked ≤ 30 minutes were given 21 mg nicotine patch (4 mg NRT gum is not available in Hong Kong). The research assistant and trained SC advisors briefly instructed the participants on the usage of NRT and gave an instruction card (eFigure 2 in Supplement 2) containing information on NRT use and potential side effects.
Does your paper address CONSORT subitem 6a? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study Data were collected in person at baseline and through telephone interviews at 3, 6, and 12months after randomization (intervention initiation). The primary outcomes were carbon monoxide-validated (<4 ppm) smoking abstinence at 6 and 12 months after intervention initiation.27 Participants who reported having quit tobacco use for 7 days or longer at the 6and 12-month follow-ups were invited for breath carbon monoxide tests. Those who agreed to the tests were given HK $300 (approximately US $38) in cash for their time and traveling expense.
Secondary outcomes included self-reported 7-day point prevalence and 24-week continuous abstinences; quit attempts; smoking reduction, defined as self-reported reduction in number of cigarettes per day by at least 50% of the baseline amount; and SC service use, defined as having attended at least one treatment session delivered by a SC service provider, at 6 and 12 months. The experienced research assistant or trained SC advisors measured participants' quality of life using the five-level EuroQol five-dimensional questionnaire (EQ-5D-5L) twice at baseline and 12 months. EQ-5D-5L has been validated in Chinese, with responses transformed using the standard Hong Kong value set form ranging from -0.864, the worst to 1, the best.
subitem not at all important 7b) When applicable, explanation of any interim analyses and stopping guidelines Does your paper address subitem 6a-iii?
Copy and paste relevant sections from manuscript text We conducted post-hoc qualitative interviews in chatbot users after the complete of the trial and reported results elsewhere.
Does your paper address CONSORT subitem 6b? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study No changes to trial outcomes after the trial commenced 7a-i) Describe whether and how expected attrition was taken into account when calculating the sample size Describe whether and how expected attrition was taken into account when calculating the sample size.
C l e a r s e l e c t i o n Does your paper address subitem 7a-i?
Copy and paste relevant sections from manuscript title (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study Sample size was estimated based on our previous trial, which found that the group receiving brief advice and active referral had a 6-month biochemically validated abstinence rate of 9.0% by intention-to-treat analysis. Given an assumed effect size of 1.8 derived from a metaanalysis of mHealth SC RCTs (RR=1.83), power of 80% and an allocation ratio of 1:1, the required sample size for detecting a significant difference in biochemically validated abstinence rates between the intervention group and control group at two-sided type I error of 0.05 is 664 (each group 332).
8a) Method used to generate the random allocation sequence NPT: When applicable, how care providers were allocated to each trial group 8b) Type of randomisation; details of any restriction (such as blocking and block size) 9) Mechanism used to implement the random allocation sequence (such as sequentially numbered containers), describing any steps taken to conceal the sequence until interventions were assigned Does your paper address CONSORT subitem 7b? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study Not applicable to our trial.
Does your paper address CONSORT subitem 8a? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study The randomization sequence with a 1:1 allocation ratio and permuted block of 4, 8, or 12 was generated by a non-investigator. Sequentially numbered, opaque, sealed envelopes (SNOSE) were prepared by an investigator not involved in participant enrolment for allocation concealment. Once a smoker signed the consent form, one SNOSE was opened according to the serial number to determine the group allocation. Masking of participants, the research assistant, and SC advisors was not possible due to the nature of behavioral interventions. Statistical analysts were blinded from the group allocation.
Does your paper address CONSORT subitem 8b? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study The randomization sequence with a 1:1 allocation ratio and permuted block of 4, 8, or 12 was generated by a non-investigator. Sequentially numbered, opaque, sealed envelopes (SNOSE) were prepared by an investigator not involved in participant enrolment for allocation concealment. Once a smoker signed the consent form, one SNOSE was opened according to the serial number to determine the group allocation. Masking of participants, the research assistant, and SC advisors was not possible due to the nature of behavioral interventions. Statistical analysts were blinded from the group allocation.
10) Who generated the random allocation sequence, who enrolled participants, and who assigned participants to interventions 11a) If done, who was blinded after assignment to interventions (for example, participants, care providers, those assessing outcomes) and how NPT: Whether or not administering co-interventions were blinded to group assignment subitem not at all important 1 2 3 4 5 essential Does your paper address CONSORT subitem 9? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study The randomization sequence with a 1:1 allocation ratio and permuted block of 4, 8, or 12 was generated by a non-investigator. Sequentially numbered, opaque, sealed envelopes (SNOSE) were prepared by an investigator not involved in participant enrolment for allocation concealment. Once a smoker signed the consent form, one SNOSE was opened according to the serial number to determine the group allocation. Masking of participants, the research assistant, and SC advisors was not possible due to the nature of behavioral interventions. Statistical analysts were blinded from the group allocation.
Does your paper address CONSORT subitem 10? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study The randomization sequence with a 1:1 allocation ratio and permuted block of 4, 8, or 12 was generated by a non-investigator. An experienced research assistant and trained SC advisors enrolled participants and assigned participants to interventions.
11a-i) Specify who was blinded, and who wasn't Specify who was blinded, and who wasn't. Usually, in web-based trials it is not possible to blind the participants [1,3] (this should be clearly acknowledged), but it may be possible to blind outcome assessors, those doing data analysis or those administering cointerventions (if any). 12a) Statistical methods used to compare groups for primary and secondary outcomes NPT: When applicable, details of whether and how the clustering by care providers or centers was addressed 11a-ii) Discuss e.g., whether participants knew which intervention was the "intervention of interest" and which one was the "comparator" Informed consent procedures (4a-ii) can create biases and certain expectations -discuss e.g., whether participants knew which intervention was the "intervention of interest" and which one was the "comparator".
C l e a r s e l e c t i o n Does your paper address subitem 11a-ii?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study Your answer Does your paper address CONSORT subitem 11b? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study Not relevant for the present study.
subitem not at all important 1 2 3 4 5 essential Does your paper address CONSORT subitem 12a? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study All analyses were performed according to a prespecified statistical analysis plan. Primary analyses were by intention-to-treat, assuming participants with missing outcomes to have had no change in smoking behaviors from baseline. Logistic regression was used to compare the SC outcomes between groups. Planned sensitivity analyses were conducted for primary analyses. First, complete case analyses were conducted by excluding participants lost to follow-up. Second, multiple imputation by chained equations assuming data were missing at random was conducted. The imputation models included the outcomes, group allocation, and sociodemographic and baseline smoking-related characteristics that were associated with abstinence or missingness, including sex, age, highest educational attainment, monthly household income, daily cigarette consumption, time to the first cigarette after waking, previous quit attempt, and readiness to quit. Fifty imputed datasets were generated and results were pooled according to Rubin's rule.
We conducted a priori subgroup analyses by baseline characteristics, including sex, age group, education level, nicotine dependence level, any previous quit attempt, and readiness to quit in 30 days. Multiplicative interaction terms of baseline characteristics × group allocation were included in logistic regression models to calculate the P values for interaction, although the study was not powered to examine interaction. In the intervention group, we examined the associations of intervention engagement, defined by IM/chatbot use (verified by WhatsApp conversation log and chatbot backend), self-reported use of NRT-S at 3 months, or both, with validated abstinence outcomes, adjusting for established predictors of SC outcomes, including sex, age, nicotine dependence, previous quit attempt, and readiness to quit. All analyses were conducted in Stata/MP version 15.1. A 2-tailed P<0.05 indicated statistical significance.
12a-i) Imputation techniques to deal with attrition / missing values Imputation techniques to deal with attrition / missing values: Not all participants will use the intervention/comparator as intended and attrition is typically high in ehealth trials. Specify how participants who did not use the application or dropped out from the trial were treated in the statistical analysis (a complete case analysis is strongly discouraged, and simple imputation techniques such as LOCF may also be problematic [4]).
C l e a r s e l e c t i o n Does your paper address subitem 12a-i? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study multiple imputation by chained equations assuming data were missing at random was conducted. The imputation models included the outcomes, group allocation, and sociodemographic and baseline smoking-related characteristics that were associated with abstinence or missingness, including sex, age, highest educational attainment, monthly household income, daily cigarette consumption, time to the first cigarette after waking, previous quit attempt, and readiness to quit. Fifty imputed datasets were generated and results were pooled according to Rubin's rule.

x26-ii) Outline informed consent procedures
Outline informed consent procedures e.g., if consent was obtained o ine or online (how? Checkbox, etc.?), and what information was provided (see 4a-ii). See [6] for some items to be included in informed consent documents. Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study All participants provided written informed consent.

X26-iii) Safety and security procedures
Safety and security procedures, incl. privacy considerations, and any steps taken to reduce the likelihood or detection of harm (e.g., education and training, availability of a hotline) C l e a r s e l e c t i o n

Does your paper address subitem X26-iii?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study Instructions and support were provided to participants, and no adverse symptoms were reported at follow-up.
Does your paper address CONSORT subitem 13a? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study Figure 1 shows that, of 711 smokers screened for eligibility, 664 participants were individually randomized. The retention rate was 69.9%, 67.2%, 73.2% at 3, 6, and 12 months, respectively. Retention rates were similar between the 2 groups (P=0.49-0.95).
subitem not at all important 1 2 3 4 5 essential 14a) Dates defining the periods of recruitment and follow-up Does your paper address CONSORT subitem 13b? (NOTE: Preferably, this is shown in a CONSORT flow diagram) * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study Figure 1 shows that, of 711 smokers screened for eligibility, 664 participants were individually randomized. The retention rate was 69.9%, 67.2%, 73.2% at 3, 6, and 12 months, respectively. Retention rates were similar between the 2 groups (P=0.49-0.95). 14a-i) Indicate if critical "secular events" fell into the study period Indicate if critical "secular events" fell into the study period, e.g., signi cant changes in Internet resources available or "changes in computer hardware or Internet delivery resources"

13b-i) Attrition diagram
C l e a r s e l e c t i o n Does your paper address subitem 14a-i?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study No critical "secular events" fell into the study period.
Does your paper address CONSORT subitem 14b? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study The trial did not end or stop early.
Does your paper address CONSORT subitem 15? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study Please see Table 1 on baseline demographic and clinical characteristics for each group.
subitem not at all important

15-i) Report demographics associated with digital divide issues
In ehealth trials it is particularly important to report demographics associated with digital divide issues, such as age, education, gender, social-economic status, computer/Internet/ehealth literacy of the participants, if known.
C l e a r s e l e c t i o n Does your paper address subitem 15-i? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study Not reported and has been acknowledged in the limitations.

16-i) Report multiple "denominators" and provide definitions
Report multiple "denominators" and provide de nitions: Report N's (and effect sizes) "across a range of study participation [and use] thresholds" [1], e.g., N exposed, N consented, N used more than x times, N used more than y weeks, N participants "used" the intervention/comparator at speci c pre-de ned time points of interest (in absolute and relative numbers per group). Always clearly de ne "use" of the intervention. subitem not at all important 1 2 3 4 5 essential 17a) For each primary and secondary outcome, results for each group, and the estimated effect size and its precision (such as 95% confidence interval)

16-ii) Primary analysis should be intent-to-treat
Primary analysis should be intent-to-treat, secondary analyses could include comparing only "users", with the appropriate caveats that this is no longer a randomized sample (see 18-i Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study Table 2 shows that, by intention-to-treat, the intervention group did not significantly increase biochemically validated abstinence at 6 months (3.9% vs 3.0%; OR=1.31, 95% CI 0.57, 3.04) and 12 months (5.4% vs 4.5%; OR=1.21, 95% CI 0.60, 2.45). Non-significant increases were also shown in self-reported 7-day point-prevalence abstinence, smoking reduction, and use of SC service at 6 and 12 months. The intervention group showed significantly higher rates of quit attempts at 6 months than the control group (47.0% vs 38.0%; OR=1.45, 95% CI 1.06, 1.97). Sensitivity analyses using multiple imputation and complete case analyses yielded similar results (eTable 1 in Supplement 2).
Does your paper address CONSORT subitem 17a? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study Table 2 shows that, by intention-to-treat, the intervention group did not significantly increase biochemically validated abstinence at 6 months (3.9% vs 3.0%; OR=1.31, 95% CI 0.57, 3.04) and 12 months (5.4% vs 4.5%; OR=1.21, 95% CI 0.60, 2.45). Non-significant increases were also shown in self-reported 7-day point-prevalence abstinence, smoking reduction, and use of SC service at 6 and 12 months. The intervention group showed significantly higher rates of quit attempts at 6 months than the control group (47.0% vs 38.0%; OR=1.45, 95% CI 1.06, 1.97). Sensitivity analyses using multiple imputation and complete case analyses yielded similar results (eTable 1 in Supplement 2).
subitem not at all important In addition to primary/secondary (clinical) outcomes, the presentation of process outcomes such as metrics of use and intensity of use (dose, exposure) and their operational de nitions is critical. This does not only refer to metrics of attrition (13-b) (often a binary variable), but also to more continuous exposure metrics such as "average session length". These must be accompanied by a technical description how a metric like a "session" is de ned (e.g., timeout after idle time) [1] (report under item 6a Does your paper address CONSORT subitem 17b? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study

19) All important harms or unintended effects in each group
(for speci c guidance see CONSORT for harms) Does your paper address CONSORT subitem 18? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study Subgroup analyses

18-i) Subgroup analysis of comparing only users
A subgroup analysis of comparing only users is not uncommon in ehealth trials, but if done, it must be stressed that this is a self-selected sample and no longer an unbiased sample from a randomized trial (see 16-iii Does your paper address CONSORT subitem 19? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study Of 85 participants who used NRT-S, 67.1% reported no side effect, while 11.8% reported headache/dizziness and 8.3% reported skin problems (eTable 2 in Supplement 2). Instructions and support were provided to participants, and no adverse symptoms were reported at follow-up.

19-i) Include privacy breaches, technical problems
Include privacy breaches, technical problems. This does not only include physical "harm" to participants, but also incidents such as perceived or real privacy breaches [1], technical problems, and other unexpected/unintended incidents. "Unintended effects" also includes unintended positive effects [2].

Does your paper address subitem 19-i?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study None was reported in our trial.

19-ii) Include qualitative feedback from participants or observations from staff/researchers
Include qualitative feedback from participants or observations from staff/researchers, if available, on strengths and shortcomings of the application, especially if they point to unintended/unexpected effects or uses. This includes (if available) reasons for why people did or did not use the application as intended by the developers.  Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study This pragmatic RCT found that behavioral support delivered through IM and chatbot combined with NRT-S compared with SMS on general health did not significantly improve validated abstinence (primary outcome), self-reported 7-day point-prevalence abstinence, smoking reduction, and use of SC services at 6 and 12 months, in proactively recruited community smokers in Hong Kong. However, engagement with the combined intervention of behavioral support through IM, chatbot, and NRT-S was low in the intervention group (11.4%, 38/332).

22-ii) Highlight unanswered new questions, suggest future research
Highlight unanswered new questions, suggest future research.
C l e a r s e l e c t i o n

Does your paper address subitem 22-ii?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study Engagement has been a major challenge for mHealth interventions particularly for those not ready for behavior change. Future trials on mHealth SC support may balance the busy schedule of participants by extending IM-based service hours. Future SC chatbots could incorporate artificial intelligence techniques such as natural language processing and machine learning to better simulate human-to-human interaction.

20-i) Typical limitations in ehealth trials
Typical limitations in ehealth trials: Participants in ehealth trials are rarely blinded. Ehealth trials often look at a multiplicity of outcomes, increasing risk for a Type I error. Discuss biases due to non-use of the intervention/usability issues, biases through informed consent procedures, unexpected events.
C l e a r s e l e c t i o n Does your paper address subitem 20-i? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study Engagement has been a major challenge for mHealth interventions particularly for those not ready for behavior change. Similarly, we found low intervention engagement (IM only: 22.3%, 74/332; chatbot only: 4.0%, 13/332; both IM and chatbot: 7.0%, 23/332).

21-i) Generalizability to other populations
Generalizability to other populations: In particular, discuss generalizability to a general Internet population, outside of a RCT setting, and general patient population, including applicability of the study results for other organizations C l e a r s e l e c t i o n

Does your paper address subitem 21-i?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study Fifth, participants were mainly male and were mostly with a low to moderate level of nicotine dependence, without past quit attempts, and not ready to quit in the short term. The generalizability of our results was uncertain to other populations with different sociodemographic and smoking characteristics. Sixth, this trial may be less applicable to other interventions that do not refer to SC services or in other settings with limited SC services.
subitem not at all important Discuss if there were elements in the RCT that would be different in a routine application setting (e.g., prompts/reminders, more human involvement, training sessions or other cointerventions) and what impact the omission of these elements could have on use, adoption, or outcomes if the intervention is applied outside of a RCT setting.
C l e a r s e l e c t i o n Does your paper address subitem 21-ii?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study A total of 6 reminders were proactively sent by SC advisors.
Does your paper address CONSORT subitem 23? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study ClinicalTrials.gov Identifier: NCT04001972.
Does your paper address CONSORT subitem 24? * Cite a Multimedia Appendix, other reference, or copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study The full trial protocol was submitted as Supplementary 1.

X27) Conflicts of Interest (not a CONSORT item)
subitem not at all important About the CONSORT EHEALTH checklist yes, major changes yes, minor changes no Does your paper address CONSORT subitem 25? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study Role of the Funder/Sponsor: The funder had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication.

X27-i) State the relation of the study team towards the system being evaluated
In addition to the usual declaration of interests ( nancial or otherwise), also state the relation of the study team towards the system being evaluated, i.e., state if the authors/evaluators are distinct from or identical with the developers/sponsors of the intervention.
C l e a r s e l e c t i o n Does your paper address subitem X27-i?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study Conflict of Interest Disclosures: None reported.
As a result of using this checklist, did you make changes in your manuscript? * What were the most important changes you made as a result of using this checklist?
The description of the chatbot intervention. STOP -Save this form as PDF before you click submit To generate a record that you lled in this form, we recommend to generate a PDF of this page (on a Mac, simply select "print" and then select "print as PDF") before you submit it.
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B. Introduction
The need for innovative and scalable intervention for promoting smoking cessation in Hong Kong Smoking is the leading cause of death worldwide and in Hong Kong (HK) and smoking cessation (SC) is among the most cost-effective medical interventions. HK has a relative low smoking prevalence (10.5% daily smokers) but further decrease is needed (to 5%) to implement tobacco endgame policies. This is very challenging as many (95%) do not actively seek for SC services, which are free in HK [1]. Proactive recruitment of smokers in community is needed as they constitute the majority of smokers. We have developed a systematic method to recruit smokers at smoking hotspots (SH, defined as public outdoor places where smokers stop/linger and smoke) and have consecutively recruited over 6000 community smokers in the past 6 years [2]. Briefly-trained healthcare (nursing, medical) students adopt "a-foot-into-the-door" strategy to approach and recruit smokers in SH: they first ask the smokers some simple questions related to their smoking and those who answered were further invited to participate in the SC trials. Our data has shown that smokers proactively recruited at SH had comparable demographic characteristics and smoking behaviours to smokers in the general population [3].
Brief smoking cessation advice model Behavioral or psychological counseling is effective for SC but mostly are too and expensive to apply in clinical or community settings. Brief intervention such as 5As (Ask; Advise to quit; Assess willingness to make quit attempts; Assist in quit attempts, Arrange follow-up) is recommended for clinical practice in many countries. We have developed and validated a brief (<5 minute) SC advice intervention, the AWARD model (Ask, Warn, Advise, Refer, Do-it-again), delivered by trained health care students to smokers in the community [2, [4][5][6][7][8][9]. We propose to enhance our AWARD model (published in JAMA Internal Medicine [9]) by adding NRT sampling and innovative technologies including automated response system and instant messaging (IM). The novel method will be even more cost-effective and sustainable for practice.
NRT sampling (NRT-S) Although NRT is effective in reducing nicotine withdrawal symptoms and increasing quit rate by 50-70%, most smokers (80% in HK) have never used NRT probably due to perceived high-cost, misperceptions and low self-efficacy. Duration of NRT treatment varied from 8 to 24 weeks and only half smokers completed the treatment. Our study showed only 16% SC clinic users used NRT for 4-week or longer [10]. As nicotine withdrawal symptoms peak at 1-week and gradually decrease 2-3 weeks after smoking abstinence, NRT use in the initial period of abstinence to combat withdrawal symptoms is most important [11]. Studies have found NRT (1-6 weeks) sampled to Quitline users increased quit attempts, quit rate, and NRT or SC service use [12]. Our RCT has found similar quit rates at 6-month follow-up in SC clinic users provided with 1 week (27.5%) or 2-week (27.3%) NRT samples [13], suggesting minimal NRT for 1-week may attract and motivate some smokers to reduce or quit smoking, use NRT for longer, and visit SC services which provide more NRT.
NRT-S has now also been used to attract smokers in community to use SC services in HK (e.g. TWGHs ISCC).
Technology-enhanced intervention Systematic reviews have shown text messaging-based (SMS) intervention were effective to promote abstinence among smokers with modest effect sizes ranging from 1.38-1.83 [14,15]. Given the SMS design, smokers can only have very limited interaction with the computers [15]. More intensive, personalized and synchronous interaction can provide stronger psychosocial support to promote quitting among the smokers. Recent technological advances allows using IM apps (e.g. WhatsApp interaction with a trained counsellors or advisors) and automatic dialogue system (Conversation agent or Chatbot), which have been applied to promoting medication adherence and delivery of mental health interventions [16,17]. Rapid development of natural language processing (NLP), machine learning through Bigdata analysis allows using Chatbot to deliver interactive dialogues to promote health outcomes (e.g. mental health promotion [18] showed that about 95% used IM Apps daily. At 1-month follow up, among 156 smokers randomized to receive IM (AWARD baseline plus IM psychosocial support), 96% received and read our IM messages (only 3 did not read because they were not interested or too busy) and 31% chatted with the counsellors at least weekly. Many reported the messages were helpful to increase their motivation to quit (66%) and quit attempt (57%). They generally were satisfied with the interaction with the counsellor (score 8.3/10). Preliminary results showed higher self-reported quit rate in intervention (14.2%) compared with control (8.2%) (AWARD advice only) at 3-month follow-up. The unstructured text data from this trial will be used to train the proposed Chatbot.

C. Aims and Hypotheses to be Tested
(1) To assess the main effect of the Intervention vs. Control group on biochemical validated smoking abstience at 6-month and 12-month. (Primary) (2) To assess the above main effects on secondary outcomes (see below) at 6-month and 12-month.
(3) To identify the potential mediators between intervention and outcomes.
(4) To evaluate the cost-effectiveness of the interventions. (5) To understand the subjects' experience of IM/Chatbot support on SC.

D. Plan of Investigation
The CONSORT flow chart in appendix 1 summarizes the timeline of the proposed study.

Settings
We aim to include a reasonably "representative" or unbiased sample of SH at different locations from all 3 major regions (HK Island, Kowloon and New Territories) of HK. A sampling frame of all SH is not available and cannot be established within this proposal. We have identified 15 hotspots and recruited 750+ smokers in 4 months in 2015. The locations of SH include exits of underground transit and railway stations, shopping malls and large commercial buildings [5]. We will select 15 more SHs from the field observation results of public open places across the 3 major regions, making up a total of 30 SH for recruitment. A trained observer will count pedestrian flow, number of smokers and assess the suitability of the environment for delivering intervention (including smokers' duration of stay, noise level, space) using improved standardized forms.
Subject recruitment Two trained SC advisors (student helpers) and 1 supervisor (experienced research nurse) will conduct intervention in each session. Potential subjects at the SH will be approached using the "a-foot-into-the-door" strategy (see "Introduction"). If there are more than 1 potential subjects, the SC advisors will randomly select 1 smoker to avoid contamination (as they may share information from IM Apps subsequently). Smokers will be assessed for eligibility and informed written consent will be sought. Subjects will complete a brief selfadministered baseline questionnaire to provide data on socio-demographic characteristics and smoking (see "Measurements"). To increase Chatbot/IM App intervention compliance and reduce later hang-ups of telephone surveys, a designated study telephone number will be saved into subjects' mobile phones. This increased response rate to 80% at 1-month in our trial in 2017.

Sample size calculation
As there is no similar trial in the literature, sample size was calculated based on our previous trials. The validated quit rate for the subjects who received AWARD advice and active referral was about 9% at 6-month & 12-month follow-up and conservative assumption of an effect size of 1.8 (usual effect size for NRT-S trials), type I error 0.05, power 80% and allocation ratio 1:1, the required sample size for determining a significant group difference of biochemically validated quit rates between Intervention group and Control group is 664 (each group 332).
(2) Methods Intervention group Brief advice (AWARD model) Subjects in the intervention group will receive brief SC advice using AWARD model (Ask, Warning, Advice, Referral and Do-it-again) to be delivered by the SC advisors using about 2 to 5 minutes. Details of AWARD are as below. 1. Ask: smoking habit, quit intention and attempt, smoking reduction intention, previous quitting experience including NRT and SC use. 2. Warn: smokers will be orally warned about the harms of smoking and receive a A5-sized leaflet, which includes some shocking pictures of smoking-related diseases, and SC services information (Appendix 2). 3. Advise: smokers will be advised to quit as soon as possible and use NRT or SC services. 4. Refer: smokers will be encouraged to seek SC services for free NRT or other SC services. Those who agreed will be actively referred to their preferred SC services. The collected contact information with consent will be sent to the SC services providers for a quick appointment and follow-up. We will liaise with all SC providers for progress monitoring and data collection on service use [9]. 5. Do-it-again: Relapsed smokers (identified during follow-ups and IM conversation) will receive the "Advise" and "Refer" intervention.

NRT-S
One-week free NRT (gum or patch) will be provided with dosage based on time to first cigarette smoking after waking up in the morning and previous NRT use (standard practice and according to specific NRT product instructions). Subjects who have first cigarette <30 minutes in the morning or have previously used NRT, will receive 4mg nicotine gum or 21mg nicotine patch. Those who have first cigarette >30 minutes after waking up and have not previously used NRT will receive 2mg nicotine gum or 14mg nicotine patch. NRT use and potential side effects will be briefly explained orally based on standardized script according to the product instructions [12]. An NRT use card containing reminders of NRT use and potential side effects will be given (Appendix 3).

IM Apps and Chatbot
Twelve-week personalized behavioural support will be delivered using interactive communication technologies using (1) regular tailored messages on abstinence, and (2) synchronousIM Apps conversation with trained SC advisors, and (3) a Chatbot. Their design will be guided by the Social Cognitive Theory (SCT) and Transtheoratical Model (TTM), which have been used in previous text-messaging-based SC trials [19,20]. SCT posits that personal factors (cognitive, affective and biological events) and environmental factors affect behavioural changes. TTM postulates that smokers undergo 5 stages of change (precontemplation, contemplation, preparation, action, and maintenance or relapse) to achieve abstinence. Details of the intervention are as below: (1) Regular tailored messages based on the subjects' surnames, socio-demographic characteristics (gender, occupation), smoking habit at baseline (nicotine dependence level, readiness to quit) and updated smoking status (smoking, quitting or relapsed) obtained during IM Apps conversation will be delivered through IM Apps (SCT). For smokers who set a quit date at baseline or during subsequent conversation through IM Apps, reminder messages will be sent before the quit date, followed by motivational messages that encourage abstinence to prevent relapse (TTM).
(2) IM Apps conversation with trained SC advisors is an extension of our baseline face-to-face AWARD intervention. Trained SC advisors will provide synchronous, personalized, interactive psychosocial support through IM conversation to help smokers to walk through the quitting process. Importantly, IM Apps allow advisors to provide timely responses to smokers' messages. These include providing support to avoid or handle high risk situations of smoking (e.g. cigarette invitation from friends, stressful events, boredom); and to break the habitual smoking by timely event-oriented messages (e.g. first cigarette in morning, smoking after meals, smoking during breaks at work). Advisors will also periodically proactively send IM messages in addition to regular messages described in (1) to initiate the conversation (e.g. asking recent progress of SC) and deliver evidence-based advice guided by the SCT and TTM. Advisors will actively refer smokers, if they have expressed the need, to SC services providers. A standard operation algorithm for SC advisor used in our pilot feasibility trial (ClinicalTrial.gov ID: NCT03182790) will be modified for use.
(3) A Chatbot will be built using open source NLP and machine intelligence platforms by the principal investigator (with knowledge and skills to be acquired through training and attachment to Harvard and MIT) and co-investigators (co-I's; Prof Kwok and Dr Kwok, computer engineers with rich experiences in developing interactive Chatbot for various purposes). In order to train the Chatbot to recognise Cantonese language (such as "點樣可以戒煙 ah?", "D 煙好貴"), a sequence-to-sequence neural network learning model will be developed. Our previous study (ClinicalTrials.gov ID: NCT03182790) on using WhatsApp to provide behavioural support for SC has recorded the conversation between over 200 smokers and advisors for 3 months. The unstructured text data will be used to train the proposed Chatbot (Appendix 4 shows examples of the text messages). Based on our previous extensive experience on SC counselling and the above-mentioned unstructured data, we will draft responses for each identified question (see Appendix 5 for examples), which will be further refined according to comments from experienced counsellors in TWGHs Integrated Smoking Cessation Center (ISCC, the largest SC service in HK, co-I Ms Chan). The completed responses algorithm will be reviewed and revised by smokers attending ISCC, SC counsellors and nurses. The prototype will then be pilot-tested in 5 smokers recruited from SH and will be revised according to their comments. The final version will be incorporated with Application Programming Interface (API) integration into user-friendly apps (iOS/Android/web app) with a backend server support and continuous data collection for potential bigdata analysis.

Control groups
The Control group will receive the same AWARD intervention as Intervention group at baseline but without NRT-S. At follow-up, they will receive regular SMS messages with content on general health and reminding the importance of participating in the follow-up surveys and biochemical validation for quitting. Our previous trial found regular SMS message on general health did not affect quitting [2]. Randomization and allocation concealment Block randomization with blocks of 4/8/12 in random order will be used to individually allocate subjects into intervention or control groups with equal size. To conceal SC advisors from the random allocation sequence, a co-I (DYTC, a statistician) will prepare 664 identical, A5-size, sequentially numbered, opaque, sealed, envelopes (SNOSE). Each envelop will contain a card indicating the subject's allocation. Once a smoker has signed the consent form, an SC advisor will open one SNOSE according to the serial number to determine the group allocation. To avoid intervention contamination, each intervention will be delivered to one smoker at a time. Upon the completion of the first intervention, there will be a 5-minute interval to let the recruited smoker leave, before the next recruitment of a new smoker at the same SH. This approach will minimise the chance of the recruiting smokers who have a connection with the previous subjects.
(4) Data processing and analysis Outcomes The primary outcome is CO-validated (<4 ppm) smoking abstinence at 6-month and 12-month follow-up, which are the gold standard to determine abstinence in many SC trials [21,22]. Secondary outcomes include self-reported 7-day point prevalence and continuous (24-week) abstinences, quit intention and attempts, smoking reduction (self-reported reduction in number of cigarettes per day by at least 50% of the baseline amount [23], calculated with inclusion and exclusion of quitters), nicotine addiction level (Heaviness Smoking Index), NRT and SC service use at 6-and 12-month. Change in quality-adjusted life year (QALY) will be estimated using the validated Chinese five-level EuroQol five-dimensional questionnaire (EQ-5D-5L) measured at baseline and 12-month to determine the incremental cost-effectiveness ratios of the intervention when compared to control (please see statistical analysis) [24]. Outcome assessors conducting the follow-up surveys will be blinded to the group allocation.

Measurements
Data (see table) will be collected at 3-, 6-and 12-month after recruitment using telephone surveys, each with an incentive of HK$50 cash coupon (total $150). Face-to-face exhaled CO validation tests using Smokerlyzer will be conducted at 6-and 12-month. HK$300 will be provided to subjects who completed each CO validation to compensate for travel expenses and time (total $600). Our experiences show that such incentives can substantially increase the response rate. Tablet PCs installed with Computer Assisted Patient Interview (CAPI) system will be used to collect data. The CAPI has built-in functions against errors and can easily generate datasets for progress monitoring and analysis, thus reducing the costs of data entry and cleaning. An electronic questionnaire using brief (<2 minutes) and validated questions (which have been used in many of our previous trials and by others) will be designed to measure the outcomes, and to maintain a higher retention rate and applicability in real-world practice. The questionnaire content is summarized as followed: Statistical and qualitative analysis Intention-to-treat (ITT: most conservative approach in RCT) analysis will be used. The primary analysis includes: (1) Main effect: Intervention vs. Control on biochemically validated abstinence at 6-month and 12-month The secondary analyses include: (2) Main effect adjusting for baseline difference (3) All secondary outcomes (see above) at 6-and 12-month (4) Mediation analysis of 3-month factors (psychosocial or resource effects) on biochemically validated abstinence at 6-month (and 3-and 6-month factors on 12-month outcomes) (5) Subgroup analyses based on intention to quit at baseline, SC service /NRT use at 3-month (6) Cost-effectiveness analysis over the 12-month trial period and long-term cost-effectiveness analysis over the lifetime horizon (please see below) (7) Qualitative study among quitters and non-quitters to understand the effects of the intervention (8) Text-mining analysis of semi-structured and unstructured data from Chatbot and IM Apps Sensitivity analyses (e.g. complete case or per-protocol) will be conducted, depending on the actual pattern of missing data, with different methods of statistical imputation (e.g. multiple/simple imputations/Last Observation Carried Forward) to assess the robustness of the findings. For the outcomes from multiple time points (3-, 6-and 12-month), linear mixed models, which allow for multiple observations between subjects and within subjects, will be used. Main effect and interaction effect will be included. Structural equation modelling will be used to assess direct and indirect effect of potential mediators (including self-efficacy on quitting, perceived support and SC services use) on outcomes. The content of Chatbot and IM Apps conversations will be recorded and analysed using skills acquired from the training (with assistance from co-Is) such as sentiment analysis, term frequency and topic modelling, which are common methods used in Bigdata analysis for text data.
Cost-effectiveness analysis of the intervention using standard methods by will be conducted by PI with assist from a co-I (Dr CK Wong, a health economist) [25]. For short-term cost-effectiveness, the empirical RCT data will be used to evaluate the effect in 12-month period. An ingredient approach will be used to estimate the cost of the intervention program including intervention materials (e.g. leaflet), administration fee, and time for SC advisors to deliver the intervention, whereas the healthcare resource use with respect to general and specialist outpatient visits, length of hospital stay, emergency visits will be measured for each subject in the Intervention and Control groups. The health effectiveness outcomes will include the number of quitters at 12month and QALY gained. EQ-5D-5L utility scores at baseline and follow-up assessments will be used to construct QALY using area under the receiver operating characteristic curve approach. For long-term costeffectiveness simulation to model the lifetime effect, a Markov model will be developed using the 12-month quit rate and relapse rate estimate taken from the RCT, and annual transition probabilities of smoking-related morbidities (e.g. COPD, lung cancer, stroke) taken from the literature. A perspective of healthcare provider will be taken and 3% discount rate will be applied. Treatment costs for smoking-related morbidities will be extracted from the literature. Setup and ongoing costs of the intervention and healthcare costs in both intervention and control groups will be derived from the RCT. Incremental cost-effectiveness ratios in the form of incremental cost per incremental life-year gained or QALY gained from intervention will be calculated over the lifetime of the simulated cohort. Deterministic and probabilistic sensitivity analyses will be conducted to test the robustness of the model.
A qualitative approach will be adopted for understanding experience of subjects in the intervention group by a Co-I (Dr JJ Lee, a qualitative researcher). The subjects will be recruited from subgroups based on smoking status at 12-month (quit, not quit) and Chatbot/IM Apps conversation involvement (>10 or <10 times). Semistructured, individual interview will be conducted on at least 20 (N=5 for each subgroup) subjects with study endpoint determined by data saturation. All interviews will be audio-recorded and transcribed verbatim. Transcripts will be analyzed using thematic analyses in NVivo 11. Codes, categories and themes generated will be compared with the established taxonomy for evaluating intervention quality related to behavioural change technique for SC.
Training of SC advisors & intervention fidelity 10-15 undergraduates from health care disciplines will be trained as SC advisors in 1-day workshop. Which includes knowledge and skills related to SC, and specific skills on IM Apps use and responses by experienced IM researchers. We have extensive experience (more than 300 trained) on short and intensive SC training in many of our previous SC projects. Those who pass the written test will be qualified as an SC advisor. All the procedures will be clearly instructed using standard operation protocols. 10% of the recruitment sessions in the early phase of the trial will be randomly selected for checking for intervention fidelity using standardized forms. Experienced SC counselor will standby as a back up to handle any questions and problems by  . Instruction card of nicotine replacement therapy. Front contents included methods of use nicotine gum, such as chewing the gum slowly for about 10-15 times, parking the gum between your cheek and the ivory inlaid bed for about 1-2 minutes, repeating these steps for about 30 minutes until the taste becomes faded, etc. Back contents included methods of use nicotine patch, such as applying a new patch each day to non-hairy sites of your body including arms, back, and abdomen, may still use the patch when you swim or have showers, etc. Figure 3. Layered structure of the chatbot. Note: The structure of the chatbot included 5 layers. Layer 5, which refers to detailed responses to specific sub-themes in layer 4, are not presented due to the length limit. Example response in layer 5 can be found in Table 1 below.  How to use nicotine patch? You can apply a new patch each day to arms, back, or abdomen. Quitting smoking on one's own Try lengthening the interval between each smoking and reduce numbers of cigarettes smoked each day.

Identification of specific cues and contexts
Please tell me about your current location, such as near your home, company, etc. Or if someone close by is smoking right now.

Reinforcement of quit motivations
Quitting smoking can protect the health of you and your family. Tips to reduce cravings Try changing your morning routine (such as the order of breakfast and bathing).

Reinforcement of quit motivations
Quitting smoking can save money.

Strategies to improve confidence
You may have tried successfully overcoming difficulties at work or persevering in learning a new language. You can apply these successful experiences to smoking cessation actions!

New tobacco products
Introduction to the products E-cigarettes are new tobacco products in which aerosol is delivered by heating a liquid that usually contains nicotine.

Health effects
The harm of e-cigarettes should not be underestimated. Ecigarettes can produce harmful substances and carcinogens after heating and vaporizing chemical substances at high temperatures.

Marketing strategies
Be careful! The packaging of most e-cigarettes may mislead consumers with words such as "not addictive", "certified", and "environmental protection." Other frequently asked questions -Withdrawal symptoms such as stress and irritation are common. Have a chat with your friends is a good way to change your current mental state.
Input textbox -Please enter your question. Our smoking cessation advisors will reply to you as soon as possible during office hours. Thank you! Figure 5. Screenshots of the chatbot "Quit Buddy". Interface of the main menu (A) allows participants to click into themes on quitting methods, coping with cravings, improving self-efficacy, new tobacco products, other frequently asked questions, and an input textbox. Interface of the example theme "coping with cravings" (B) allows participants to interact with subthemes on identification of specific cues and contexts, reinforcement of quit motivations, and tips to reduce cravings. Interface of the input textbox (C) allows participants to make enquires to live smoking cessation advisors.